Study the chart above to find the plague during which the greatest percentage of population perished. Which of the following contributed most to the high death toll?
a.
No walls existed in this city to keep the plague out.
b.
A wall built to fortify the city isolated the disease inside the city.
c.
The Emperor Justinian was struggling to unite the failing empire.
d.
All of the nobility left the city for their homes in the countryside.